ST. PETERSBURG, Fla. -- Alex Cobb wasn't sure if he should be elated or disappointed.

The Tampa Bay pitcher struck out 13 in fewer than five innings against the San Diego Padres on Friday night. The Rays won 6-3; however, Cobb didn't feel as though he'd truly done his job.

"I don't know if that's a good thing," Cobb said when told he'd become the first player in major league history to fan that many batters and fail to make it through the fifth. "As a starting pitcher, you want to go at least five innings every time out."

The right-hander left after throwing 117 pitches. He recorded 12-of-14 outs on strikeouts -- four of them in the third, when a wild pitch on strike three allowed Will Venable to reach base.

The other outs were recorded on grounders to shortstop in the first and third base in the fourth.

"I can't really explain why or how that happened. It was just one of those weird days," Cobb said. "Obviously, that's not my goal. I never go into a game trying to strike everybody out. I was trying to put balls over the plate and have them make weak contact, and they were swinging and missing."

The Padres struck out 18 times.

"He had his changeup going and it was tough to differentiate that from the fastball, and he had us on our heels the whole night," Venable said. "He pitched really well, and we just weren't able to make the adjustment."

Roberts and Zobrist both delivered two-run singles in the seventh, when reliever Dale Thayer (0-2) inherited a 3-2 lead from Padres starter Edinson Volquez. Jake McGee (1-2) pitched one inning for the victory, and Fernando Rodney worked a scoreless ninth for his fifth save.

Venable and Carlos Quentin hit solo homers off Cobb in the first for San Diego. Chris Denorfia also singled twice off the Tampa Bay starter, who allowed three runs, five hits, one walk and hit a batter.

Trailing 3-2, Cobb struck out Chase Headley and Quentin to begin the fifth. He was removed after walking Yonder Alonso, ending a streak of Tampa Bay starting pitchers working at least five innings in every game this season at 34 -- the second-longest stretch to begin a season behind the 1981 Pittsburgh Pirates (45).

Rays manager Joe Maddon had no regrets about not allowing Cobb to continue.

"I just could not permit it and feel good about myself at that point. His career is way too important to him and his family and to us," Maddon said.

"At the end of the day it's about the Rays. And for me, it's about the future of these players. ... To have him injure himself because he's going to throw 125 pitches in five innings, that would be on me. You have to be careful at that point."

Umpires Fieldin Culbreth, Brian O'Nora, Bill Welke and Adrian Johnson worked the game. Earlier in the day, Major League Baseball suspended Culbreth for two games because he was in charge of the crew when it allowed Astros manager Bo Porter to improperly switch relievers in the middle of an inning on Thursday.

Culbreth, O'Nora, Welke and Johnson were also fined an undisclosed amount after MLB admitted its umpires made a mistake for the second straight day.

Culbreth told a pool reporter after Friday's game that he takes "all the responsibility" for what happened.

As for the discipline?

"I look at it that baseball has high standards for their umpires and I have high standards for myself and I didn't meet those standards last night, so I am absolutely OK with everything," Culbreth said.

Cobb had nine strikeouts in the first three innings. He worked an extended third, when his wild pitch enabled Venable to reach base. The Padres center fielder stole second and third base, then scored on a balk to make it 3-0.

The Rays starter became the second Tampa Bay pitcher to fan four batters in an inning, joining Jeremy Hellickson, who did it against Detroit on Aug. 25, 2011.

Volquez allowed three runs and three hits in six innings. Evan Longoria had two of the hits off the right-hander, including a RBI single in the third. Tampa Bay a second run in the third on a wild pitch.

Game notes
RHP Burch Smith will make his major league debut for the Padres on Saturday night. The 23-year-old was called up from Double-A San Antonio, where he was 1-2 with a 1.15 ERA in six starts. Manager Bud Black has seen Smith pitch only once, in the 2011 Arizona Instructional League, and Smith has not pitched at the Triple-A level. "I'm happy for him," Black said. "Our minor league people thought that he was the guy, so we'll see it (Saturday)." ... The Rays placed RHP Brandon Gomes on the 15-day disabled list, retroactive to May 8, with a strained muscle in his right side. To fill his spot in the bullpen, RHP Josh Lueke was recalled from Triple-A Durham. ... Tampa Bay C Jose Molina is day to day with a bruised right knee. He was injured when he was hit by a foul tip during Thursday night's victory over Toronto.